High voltage circuit breaker



May 5, 1964 s. P. HERMANN HIGH VOLTAGE CIRCUIT BREAKER 4 Sheets-Sheet 1 Filed D60. 28, 1961 May 5, 1964 G P. HERMANN HIGH VOLTAGE CIRCUIT BREAKER 4 Sheets-Sheet 2 Filed Dec. 28, 1961 May 5,1964 G. P. HERMANN 3,132,222

HIGH VOLTAGE CIRCUIT BREAKER Filed Dec. 28, 1961 4 Shets-Sh'eet s 4 Sheets-Sheet 4 G. P- HERMANN HIGH VOLTAGE CIRCUIT BREAKER May 5, 1964 Filed Dec. 28, 1961 HEW/70727? 5% 1 3,132,222 HiGl-I VQLTAGE cmcrnr BREAKER Gerald P. Hermann, Pittsfield, Mesa, assignor to General Electric Company, a corporation of New York 1 Filed Dec. 28, 196i, Ser. No. 162,83? 6 Claims. (Cl. Zeb-116) This invention relates to circuit protective devices for electrical apparatus, and more particularly, to a high voltage circuit breaker for use on the high voltage side of an electrical apparatus. r

In application Serial No. 162,876, now Patent No. 3,112,383 for a Combined High Voltage Circuit Breaker and Fuse filed. concurrently herewith in the name of Sidney R. Smith, Jr. and assigned to the same assignee as this invention, there is disclosed a combination circuit breaker and fuse assembly for an electrical apparatus in which theassembly is designed to be connected to the high voltage side of such electrical apparatus to provide protection against faults in such apparatus, as well as overloads which may be experienced by the apparatus. In designing the novel circuit breaker and fuse combination of that application, it was found desirable to incorporate a novel type of circuit breaker therein, one which would be more easily co-ordinated with the fuse of such combination.

United States Patent As is clearly set forth in the aforementioned patent application Serial No. 162,876, it is desirable that both the fuse and the circuit breaker be properly co-ordinated such that the circuit breaker will operate to de-energize the high voltage side of the electrical apparatus to which it is attached for all overloads and fault currents which are less than the short circuit current of the electrical apparatus. However, for fault currents which are substantially equal to or greater than the short circuit current of the electrical apparatus, it is desirable that the fuse blow to de-energlze the high voltage side of the electrical apparatus such that the apparatus may notbe put back into operation by closing of the circuit breaker, which is connected in electrical series with the fuse. As is well understood by those skilled in art, a fault current which is substantially equal to or greater than the short circuit current of an electrical apparatus is generally indicative of a major fault in the electrical apparatus. Clearly, it is desirable at this point to remove the entire electrical apparatus from the line, and to prevent a lineman, or other maintenance personnel, from being able to manually close the circuit breaker. and temporarily put the electrical apparatus back on the line where such a major fault is, indicated in the electrical apparatus. Such apparatus should be removed from the line and thus it is desired that the fuse blow before the circuit breaker opens.

As is well understood in most types of electrical apparatus, the primary or high voltage side of such electrical apparatus While being subjected to large voltages is in general only carrying relatively small current. In placing a high voltagecircuit breaker on the high voltage side of such electrical apparatus, it is of course, necessary that the circuit breaker be designed such that for small changes in current and for the small current which is present in the high voltage side which would indicate an overload or fault in the apparatus, the high voltage circuit breaker must positively operate to open the high voltage side of such electrical apparatus. Thus, one of the desirable design criteria of the high voltage circuit breaker of this invention is that it be able to carry the small currents which are normally present in the high voltage side of such electrical apparatus and that for small increases in such high voltage current that the cir-.

cuit breaker be positively operated so as toopen the high voltage side of the electrical apparatus.

- in the art, many 2,132,222? Patented May 5, 1964 Of course, as will be understood, in designing a cir-' cuit breaker which will operate for small changes in current in the high voltage side of an electrical apparatus a problem arises in that small changes in the current on the low voltage side may cause the undesired operation of the circuit breaker. For example, when a customers home is subjected to a short circuit, an increase in current is reflected back into the electrical apparatus and such increased current may be sufiicient to cause operation of the circuit breaker prior to the operation of the fuse in the customers home. Further, when the secondary lines are momentarily in contact, such as by a high wind, also a fault current is reflected back into the electrical apparatus and such fault current could also cause the operation of a high voltage circuit breaker which was designed to operate for very smallchanges in current. Obviously, the operation of the circuit breaker in such instances would unnecessarily interrupt the service provided by such electrical apparatus. Therefore, it is extremely desirable that the high voltage circuit breaker be designed so that it will not operate during momentary shorts or overloads on the secondary of the electrical apparatus.

Further, where the circuit breaker is utilized in electrical apparatus, such as transformers, which are provided with a dielectric liquid as a cooling and insulating medium, the circuit breaker is generally disposed in such liquid dielectric. As is well understood by those skilled times where overloads or small faults occur within or without the transformer, which are not of suificient value to cause operation of the circuit breaker,

such small fault causes a continuous heating of the dielec-, As the liquid heats trio liquid of the electrical apparatus. up it will be understood that it eventually reaches a sub stantially dangerous temperature at which time it is desirable that the electrical apparatus be de-energized, regardless of the amount of current presently flowing in the electrical apparatus. It is, therefore, desirable that the circuit breaker which is utilized on the high voltage side of such electrical apparatus be provided with a temperature sensitive means such that when the liquid dielectric in which the circuit breaker is disposed obtains a predetermined temperature that the temperature sensitive means will operate to open the circuit breaker and thus de-energize the high voltage side of the electrical apparatus.

It is therefore one object of this invention to provide a a high voltage circuit breaker for use in a circuit breaker and fuse combination which may be readily co-ordinated with the fuse of the combination.

It is another object of this invention to provide a high voltage circuit breaker which has a delayed operation so that it will not open for momentary shorts, overloads, or magnetizing inrush currents, to which the electrical apparatus is subjected.

Another object of this invention is to provide a high voltage circuit breaker which has a temperature sensitive means to provide operation of the circuit breaker if the liquid dielectric in which such circuit breaker is disposed obtains a predetermined temperature regardless of the current circulating in the circuit breaker.

A further object of this invention is to provide a high voltage circuit breaker having current sensitive means of novel design to provide positive operation of the circuit breaker for small fault currents in the high voltage portion of an electrical apparatus.

Another object of this invention is to provide a high voltage circuit breaker having manual operating means, the breaker being designed such that if manually re-closed on a fault, the breaker will re-open, even thoughthe In carrying out this invention in one form, a circuit increases 1n 7 in circuit with load and fault currents.

breaker is providedfor connection tothe high voltage side of an electrical apparatus. The circuit breaker is provided'with current sensitive means operable on small current to unlatch' a spring operated means to cause the circuit breaker to open. Further, a temperature sensitive means is provided mounted on the circuitbreaker' so as to provide the unlatching function if the temperature of the liquid dielectric exceeds a predeterminedte mperature regardless of the current flowing in the ele ctrical apparatus.

The invention W ich is sought to be protected will be particularly pointed out and distinctly claimed in the claims which are appended hereto.

various objects and advantages are obtained, 'as well as other objects and advantages thereof, will be better understood from the following detailed description of a preferred embodiment thereof, when'taken in conjunctionwith the accompanying drawings, in which:

FIGURE 1 is'a plan view, partly in section,

with

breaker shown in FIG. 2 with the parts in open position;

FIGURE 5 is a plan view of the side of the circuit breaker shown in' FIG. 2 with the parts in their closed osition; a 7

FIGURE 6 is a partial plan View of the side of the circuit breaker shown in PEG. 3 with thepartsin closed position; and 7 FIGURE 7 is a time current curve showing the desiredrelation between the time current characteristics of a fuse and circuit breaker when used in combination to protect an electrical apparatus. 7

Referring now to the drawings, in which like numerals are used to indicate like parts throughout the various views thereof, and with specific reference to'FiG. 1 there 7 I However, it is'be 'lieved that this invention and the manner in which its showing a one form of the high'voltage circuit breaker of this inis shown a combined circuit breaker and fuse connected former, to protect such apparatus from dangerous over- The combined circuit breaker and fuse assembly as shown claimed in greater detail in the Application Serial No. 162,876 previously mentioned herein. The combined circuit breaker and fuse comprises a is shown as being mounted within a ceramic bushing 12 and having a terminal 14 thereon which terminal is adapted to be connected to a high voltage line as is well understood by those skilled in this art. hO ne endof the fuse 10 is electrically connected to the terminal 1 while the opposite end of the fuse ltliselectrically connected to a terminal member 16 at the" lower end of theceramic bushing 12. The circuit breaker is connected electrically in series with the fuse ill and is shown as compris-' ing a circuit breaker 18 which has a mounting board 19 and'pivotally mounted thereon is the'movable breaker contact 2b, which makeselectrical contact within explo sion' pot 21 with a spring loaded terminal member '22. Terminal 22 .is preferably mechanically and electrically connected to terminal 16 at the lower end of the ceramic bushing .12 The circuit breaker contact Zil'is mounted on a pivotal arm 24 which has connected thereto an electrical lead 26. Lead Zdis connected to the bimetallic current sensitive member 28. Another lead 3% extends from the bimetallic current sensitive member 2% to a terminalbo'ard 19. From the terminal board 32 the. primary winding lead 34 is connected to the primary winding of the core and coil unit 36 of the transformer 3E. it can be seen that the electrical power from the high in PEG. 1 is described and fuse member it) which 7 an electrical apparatus, such as a trans- 'sulating mounting voltage line "comes into the electrical apparatus at the terminal 14 through the current lirniting fuse 10, terminal 16 at the base of ceramic bushing 12, to the terminal 22 in explosion pot Zi, through contact 2% and arm 24 and lead 26 to the current sensitive bimetallic member 23. 'From the bimetallic element 28 the power is carried by lead 30 to terminal board 32 and then through or to the grounded neutral of a three phase line. Obvionsly, the connection. will depend upon the type and service of the electrical apparatus. The mounting board 190i the circuit breaker 18 is connected by means of inmember 42 and the mounting strap 44 to the cover of the electrical transformer 38. I Also, the circuit breaker is provided with a manual operating arm 46 which is connected to the circuit breaker is and which is connected at its opposite end by'means of a crank or link 48 to an operating handle 50 which is mounted exteriorly of the electrical transformer. From the above it can be seen that the high voltage circuit breaker and fuse connected to the electrical apparatus is serially connected such that the current which traverses the fuse It) also fiows'through the current sensitive member 28 of the circuit breaker, whereby both the circuit breaker and, iuse are subjected to the same overloads or fault currents. 'As hereinbefore mentioned, the combined circuit breaker and fuse assembly is described and claimed in the co-pending, application Serial No. 162,876, of Sidney R. Smith,-lr.,

the aforementioned patent applicaf a detaileddescription of the construction and. operation of the novel circuit breaker of this invention. As shown in these figures, the circuit breaker 18 is comprised of a mounting board 19 on which the various portions of the circuit breaker are mounted. The principal electrical parts of the circuit breaker in are the contact Zii, which is in the form of a rod member for contacting theterminal 22 within the explosion pot 21 and the bimetallic, current carrying member 28 which is connected electrically to the the pivot member 6%) which 32, which is mounted on themounting board in this manner also connected to the apparatus through the the primary lead 34.

contact 26 by the lead 26 and'is primary winding of the electrical lead 3%, terminal board '32, and The circuit breaker contact arm 24 which is pivoted on the mounting board -19 about mounting board 119. Thearm 24 is slightly V-shaped, and fastened near the apex of the 'V is. a pin member 62 which pivotally and slidingly secures the enclosure 66 or spring 64 to the arm 24. Thespring member 64 may be characterized as an over center compression spring which is designed to firmly lock the contact member Ed in electrical connection with the terminal 22 Within the explosion pot 21 when the circuit breaker is in its closed position. in order to enable thecompression spring 64 to adequately compress within its opening 68 is provided on opposite sides of the enclosure member to allow the closure'member 66 limited'movement about the pin member 62. Further, in order to keep the compression spring 64- from buckling through the open side of enclosure 66, a" securing means in the form of a rod member 74? is provided. One end of the rod member '7 ii passes through an opening 72 in the lower end of the spring enclosure 66 and above pin 62, While the other end rides over the top of a pin member 74, which is mounted through the top end of the spring enclosure '66. A second spring member 76 is also connected to the the combined high voltage. circuit 2th is mounted on a pivotal is firmly attached .to the enclosure member 66 a slotted being secured to a cross member 78 on the arm 24. The

opposite end of spring 76 is connected to a stub member 79 firmly fixed in the mounting board 19 such that when the arm 24 is moved into position in the explosion chamber 21 the spring member 76 is placed in tension by the move ment of the arm 24. Also, as can be seen the lead men1- ber 26 is attached to arm member 24 by means of bolt 88, the electrical connection between the bolt 80 and the terminal 26 being provided by the metallic material of the arm 24. Of course, as will be understood, if desired the lead member 26 could be connected directly to contact 20.

As indicated earlier, the opposite end of spring en closure 66 has a pin 74 therethrough which maintains the spring 64in compression with the enclosure 66 and also enables the end of the spring retaining means 70 to retain the spring 64 within the enclosure 66. Pivotally mounted about the pin 74 is a link member 82 which has its opposite end pivotally connected to a second link 84 by means of the pin member 86. .Spring mounted within the link member 84 is one portion of a latching means in the form of a flat latch member 88. The member 88 is provided with a slotted opening 90 which surrounds the pin member 86 and is movable thereabout, and on its opposite end is provided with a slot 92 which is mounted about the pivot member or shaft 94. The pivot member 94 secures the pivoting link 84 to the mounting board 19 and allows it to pivot about the member 94. The spring member 96 is connected atone end to the tab 98, which is formed on the flat latch member 88 when the slot means 92 is formed, the opposite end of spring 96 being secured about the pin member 86. As will be apparent the spring member 96 is in tension forcing the latch member. 88 in a downward direction, such that the upper portion of the slot 90 is her 86. However, it can be seen that the opposite end of the latch member 88 is provided with a sloping side 89, such that it may ride over the lock portion 106 of the latching means. The other side of latch member 88 is straight, as at 91, to thereby prevent clockwise rotation of the link 84 and latch member 88 when latched with lock 186, as will be more fully described hereafter.

The locking portion 188 of the latch means is held in its upward or lockingposition, shown in FIG. 2, by means of the tension spring 162 which is connected to lock means 160 by means of a harness 104. The opposite end of spring 1tl2'is connected to atab 186 formed on the mounting board 19. As can be seen, especially from FIGS. 2 and 3, lock means 108 is in the form of a crankshaft or U-shaped member, one end beingpivotally mounted in bearing member 168 fixed to the mounting board 19 by bolts 169, while the opposite end is pivotally mounted through an opening 110 in the mounting board 19.

Referring now specifically to FIG. 3, but in consideration with FIG. 2, the locking means 188 is formed from a portion of a rod member 112 which is disposed on the opposite side of the mounting board 19 from the portions which have just been described. The rod member 112 is provided on its end with a pivoted lever means 114, the lever being pivotally mounted about a turned end 115 of the rod member 112. The pivoted lever 114 is maintained in its level, interfering position, shown in FIG. 3, by means of a spring member 116 which is turned or wrapped about the end 115 of the rod member 112 and has one end engaging the top portion of the lever 114, as shown at 118, while the opposite end is twisted in engagement with rod member 112. A flat portion 120 is provided on the pivot lever 114 which butts against the rod member 112through action of the spring 116, in the manner clearly shown in FIG. 3. Thefiat portion 120 acts as a vane member, to provide a time delay in opening of the circuit breaker, as will be more fully described hereafter. The pivoted lever 114 at the end of rod memher 112 cooperates with the locking means 106 of the firmly against the pin mem latch means by striking against a rotatable shaft member 122, which is rotatably mounted in the mounting board 19. When the latch means 88 engages the lock means 108, and the circuit breaker is in its locked position, as shown in FIG. 5, then the compression of spring 64 attempts to force the latch member 88 to pivot the lock means 188. At this point, the spring 102 which holds the locking means in its upright locking position is not sufliciently strong to overcome the combination of other spring forces and thelock means tends to pivot thereby forcing rod member 112 and the pivoted lever 114 into interfering position with the rotatable shaft 122.

member 88 is maintained in engagement with the lock means 166 preventing the circuit breaker 18 from opening.

In order to provide for opening of the circuit breaker automatically, due to over current conditions the electrical apparatus which the circuit breaker is protect ing, a current sensitive bimetallic element 28 is provided, the element 28 being wrapped about the shaft 122 in the mannercleanly shown in FIG. 3. As earlier mentioned lead 26 brings the electric power from the line to the bimetallic element 28 and thence through bimetallic element 28 and by means of lead 36 to .the terminal board 32 and thence to the primary winding of the electrical apparatus. As shown, the bimetallic element is composed of a nurnb er of strips of metallic ribbon which are electrically in series but mechanically in parallel, and are coiled about the shaft member 122. The inner endsyof the ribbon forming the bimetallic element 28 are mechanically secured together through an insulating member to the rotatable shaft 122 and, at the same time, are electrically connected together in series. The inner portion of the shaft 122 is provided with a notch 1.24 which may be rotated in a clockwise direction to thereby release the pivoted lever 114 and allow the circuit breaker to open. As will be understood, when the bimetallic, current-car-' rying member 28 is swbjected to over currents, the element will expand thereby turning shaft member 122 in a clockwise direction to thereby bring the notched section 124 into a position which allows pivoted lever 114 and rod member 112 to move upwardly, as shown in phantom lines. This movement of rod member 112 moves lock means ltltl, allowing latch member 88 to rotate. In this manner over currents in the bimetallic element 28 will provide for operation of the circuit breaker 18 in order to open such circuit breaker when subjected to over currents. As will be understood, the size and the number of turns and strands of ribbon in the bimetallic element 28 will depend upon the rating of the electrical apparatus to which the circuit breaker 18 is to be connected. Also it will be understood that by means of the cross-sectional area of the ribbon a time delay may be built into the bimetallic element 28 to thereby prevent it from immediately, or substantially immediately, operating due to an over current in the bimetallic element 28.

In order to provide for the operation of the circuit breaker 18 of this invention, when it is submersed in a liquid dielectric and the liquid dielectric is over heated a second bimetallic element is provided, shown the form of the U-shaped member 130, which, as shown in FIGS. 3 and 6, is adjustably connected at one end to a tab 132, formed in the mounting board 19. The opposite end of the U-shaped member 138 is free and is mounted in a position just below the shaft member 122. As the liquid dielectric which surrounds the bimetallic element 130 becomes heated, bimetallic element 130 begins to expand or open about the bight of the U. Inasmuch as one end of the bimetallic element 138 is securely held to tab 132 on the mounting board 19, the opposite end of the U-shaped element 130 will tend .to move in a clockwise direction below the shaft member 122. As the end of the bimetallic element 130 moves in a clockwise direction, due to the heat of the liquid dielectric, it will engage the pivoted lever114 which is in contact with the shaft member 122.

As the bimetallic element expands it will pivot the lever 114- about the end 115 of the rod member 112 to apositio-n whichclears the, shaft member 122.1 Of course, as the pivoted lever 114 clears the shaft member 122 it enables the lockrneans 1th to be rotated to thereby release the latch member 88 to thereby allow the circuit breaker v 18 to move to open position. v I I The position of the circuit breaker pants in theiropen and'closed condition are shown more cleanly in FIGS. 4 and 5. In FIG. 4 it can be seen that the latch member .88 is in latching contact with locking means when the circuit breaker is in its open position, and is in the resetting position. a The manual setting arm 46 of the circuit breaker 13 is pivotally mounted with a slotted pin connection on the pin member 74- between link 82 and the compression spning odtsee FIG. 2). At this positime. Where the two curves cross over at 146 is substantially the short circuit current of the electrical apparatus to Whichthis circuit breaker is adapted to be used to protect is from overloads. As set forth earlier, when the overload current is substantially equal to the short circuit current of the electrical apparatus it is desirable I that the fuse blow rather than having the circuit breaker open. In order to obtain this desired characteristic, the circuitbreaker. is provided with the vane 120 previously described, and the movement of the'vane through the dielectricfluid increases the time required to release latch 19%, thereby providing a time'delayfor the larger curtion, the fixed points of the circuit breaker members are the upper portion of link 84 which is secured by bolt member 94 to the mounting block 19, the lower end of latch 88 which is, firmly locked against the locking means 11%), and the upper portion of arm 24 which is firmly secured to the mounting board 19 by means of the pin member 69. Thus, as can be, seen, when the manual closing rod 46 is moved in a downward direction the link member 84 and latch 88 will remain stationary and the link 82 will pivot about the pin 86 to force arm member 24 to rotate about point at .to cause the contact 2% to move in the direction of the explosion pct 21..

Referring now to FIG. 5, it can be seen that as the contact member 20 enters the explosion put .21 the spring means 102 is placed in tension by the force of the latch member 83 against the look means 180. At this point of course the pivoted lever 114 on the rod member 112,

I which is an extension of the lock means 1%, will be pushed into intenfering position with the rotatable shaft 122, thereby preventing the lock means 1% frorrropening. Further downward pressure on the manual resetting arm 46 will move the link 82 and the compression spring 64 into the position shown in dotted lines in FIG. 5, whereby the contact member 211 be firmly seated against the terminal 22 within the explosion pct 21, and the compression spring 64 will be in its over centered position, thereby aiding in forcing the latch member 88 in firm engagement with the locking means 1%. Of course, it will be apparent that merely by moving the manual resetting arm 46 in the opposite direction to lift latch 82:

and the compression spring 64 from the over center position will serve to release the contact member 29 from the explosion pot zlwithout disturbing the latch 88 and the locking means 160. As will also be .apparent, if the circuit breaker 18 is closedon a fault, the bimetallic member 2S will be subjected to the fault current as soon as contact 21) and terminal 22 are connected. The bimetal 2E8 function to release lock means 160 as previously described The circuit breaker 18 will then open, even. if the manual operating means 46 is held in its closed The release of lock means 10(lwill release" position.

latch means 88 allowing it to pivot about the shaft 94.

' This will relieve the compression in spring 64, allowing spring 76 to remove contact 29 from terminal 22, by pivoting 24 about pin 2t Referring now to FIG. 7 of the drawing, there are shown therein desirable time current curves which show the desired crossover between the time current characteristics of the circuit breaker of this invention and the time current characteristics of'a fuse, which may be used in combination with the circuit breaker of this invention in the manner more specifically disclosed in the aforementioned patent application Serial No. 162,876. As shown in FIG. 7, the circuit'breaker is provided with a time current curve 140 which will operate to open the circuit breaker when subjected to a small overload current for a substantial period of time. As can be seen the greater the overload .current the more rapidly the rents such that the cross over point 146 willbe obtained. However, if desired, thetotal mass of rod member 112 and lever 114 could be increased to provide a similar time delay function.

From the above it will be understood that there has been disclosed in this invention a novel high voltage cirbeen described in detail, it will be understood that various changes may be made in the construction of the various portions as well as the various types of material previously designated herein. Thus it will be understood that, while the particular preferred embodiment has been described herein, various changes and modifications which may be made are considered as coming within the scope of the invention as set forth in the claims appended hereto. I

What is'claimed as'new and'which' it is desired to secure by Letters Patent of the United States is:

1. A high voltage circuit breaker for connection'to the high voltage. side of an electrical apparatus said circuit breaker comprising, in combination; a contact means connectable to a source of high voltage power, a current sensitive means coiled about and connected toa rotatable ingmeans including a portion thereof'in contact with 7 said rotatable member, latching means contacting said locking means and. being linked with said contact member, whereby overcurrent in said current sensitive means will cause said rotatable member to rotate, thereby releasing said locking means to thereby release said latching means to allow said linking means to remove said contact from the source of electrical power.

2. A high voltage circuit breaker for conne'ction'to the high voltage side of an electrical apparatus said circuit breaker comprising, in combination; acontact means connectable to a source of high voltage power, a current sensitive means, coiled about and connected to'a rotatable member, means connecting said contact to said'current sensitive means, means'for connecting said current said locking means and being linked with saidcontact member, whereby overcurrent in said current sensitive means will cause said rotatable member'to rotate thereby releasing said locking portion which allows said locking means to release said latching means to allow said linking means to remove said contact from the source of electricalpower.

3. 'A high voltage circuit breaker as claimed in claim 2 in which said locking portion includes a pivoted member pivotable into and out of contact with said rotatable member, "a temperature sensitive device responsive to overtemperatures', said temperature sensitive device being mounted adjacent said pivotedmember whereby as said temperature sensitive device responds to over temperatures itcontacts said pivoted member to pivot it out of contactwith said rotatable member. 7

4; A high voltage circuit breaker for connection to the high voltage side of an electrical apparatus said circuit breaker comprising, in combination; a contact means connectable to a source of high voltage power, a current sensitive means coiled about and connected to a rotatable member, means electrically connecting said contact to said current sensitive means, means for electrically connecting said current sensitivemeans to a portion of an electrical apparatus, locking means including a pivotable I portion, latching means contacting said locking means,

linking meanslinking said latching means with said contact means, said pivotable portion spring biased into interfering relation with said rotatable member, said rotatable member having a notched portion, whereby overcurrent' in said current sensitive means will cause said rotatable member to rotate said notched portion adjacent said pivotable por'tion'to thereby releasing said locking means which releases 'said latchingmeans causing said linking means to remove said contact means from the source of electrical power. 1

ing means when said fluid dielectric is over temperature 7 to thereby render said manual means ineffective.

References Cited in the file of this patent UNITED STATES PATENTS 2,053,934 Atwood Sept. 8, 1936 2,053,952 Hill Sept. 8, 1936 2,162,935 Burnside Jan. 20, 1939 2,348,228 Scott May 9, 1944 2,414,554 Pierce Jan. 21, 1947 2,476,022 Bennett July 12, 1949 2,482,009 Link Sept. 13, 1949 2,614,191 Rogers Oct. 14, 1952 

1. A HIGH VOLTAGE CIRCUIT BREAKER FOR CONNECTION TO THE HIGH VOLTAGE SIDE OF AN ELECTRICAL APPARATUS SAID CIRCUIT BREAKER COMPRISING, IN COMBINATION; A CONTACT MEANS CONNECTABLE TO A SOURCE OF HIGH VOLTAGE POWER, A CURRENT SENSITIVE MEANS COILED ABOUT AND CONNECTED TO A ROTATABLE MEMBER, MEANS CONNECTING SAID CONTACT TO SAID CURRENT SENSITIVE MEANS, MEANS FOR CONNECTING SAID CURRENT SENSITIVE MEANS TO A PORTION OF AN ELECTRICAL APPARATUS, LOCKING MEANS INCLUDING A PORTION THEREOF IN CONTACT WITH SAID ROTATABLE MEMBER, LATCHING MEANS CONTACTING SAID LOCKING MEANS AND BEING LINKED WITH SAID CONTACT MEMBER, WHEREBY OVERCURRENT IN SAID CURRENT SENSITIVE MEANS WILL CAUSE SAID ROTATABLE MEMBER TO ROTATE, THEREBY RELEASING SAID LOCKING MEANS TO THEREBY RELEASE SAID LATCH- 